Date: Thu, 2 Jun 2016 14:40:14 -0700 From: Jack Vogel <jfvogel@gmail.com> To: Sreekanth Rupavatharam <rupavath@juniper.net> Cc: hiren panchasara <hiren@strugglingcoder.info>, "freebsd-net@freebsd.org" <freebsd-net@freebsd.org> Subject: Re: Possible transmit/stats problem in igb driver. Message-ID: <CAFOYbc=s0L5SQS8-1ZC5TGxYkuQpPGhpWCAMkBojNwS=jqOSvg@mail.gmail.com> In-Reply-To: <9A903EE5-3F2C-46C0-B563-1150F81E3507@juniper.net> References: <D7944476-98AD-4548-99E3-6E88648E2B06@juniper.net> <20160602202015.GG8994@strugglingcoder.info> <9A903EE5-3F2C-46C0-B563-1150F81E3507@juniper.net>
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Hmmm, so I no longer have access to any of this, but I'm wondering if there is some other stat that might report errors or some sort that would match the missing/bad packets? Maybe they were considered runts or something and dropped. Good luck :) Jack On Thu, Jun 2, 2016 at 2:11 PM, Sreekanth Rupavatharam <rupavath@juniper.ne= t > wrote: > Inline > > >Apart from stats, do you see anything else going wrong? i.e. do you > >actually see less packets (arp replies??) than expected? > > [SR] The packets are not going out on the wire. The tool doesn=E2=80=99t = receive > the packets. That=E2=80=99s how I started noticing the issue. > > >Taking your example, tx_packets is something we count in the drivers and > >total_pkts_txd is calculated in the card and we just read it off of it > >to report (E1000_TPT). > > [SR] Correct. My main question would be under what circumstance would the > packet handed off to hardware will *not* be transmitted?. Especially > considering there are no transmit errors or pause frames received. There > are no dma tx failures either. That=E2=80=99s the baffling part. I tried = another > exercise where I used ping of various sizes going out, but that doesn=E2= =80=99t > seem to trigger the problem. > > > >To understand your setup better, ixia is the sender and your box with > >igb(4) is the receiver and your are sending arp requests to it. > > Yes, correct. > > >Can you post following for working (size <=3D 64bytes) and non-working > >(size > 64bytes) cases for before/after? > > > >sysctl dev.igb | grep tx_packets > >sysctl dev.igb | grep total_pkts_txd > >sysctl dev.igb | grep rx_packets > >sysctl dev.igb | grep total_pkts_recvd > > > Before(not working): > dev.igb.1.queue0.tx_packets: 24907933 > dev.igb.1.queue0.rx_packets: 18086575 > dev.igb.1.mac_stats.total_pkts_recvd: 25057359 > dev.igb.1.mac_stats.total_pkts_txd: 16647169 > > After(not working): > dev.igb.1.queue0.tx_packets: 24913324 > dev.igb.1.queue0.rx_packets: 18091832 > dev.igb.1.mac_stats.total_pkts_recvd: 25062618 > dev.igb.1.mac_stats.total_pkts_txd: 16647545 > >netstat -sp arp > > The difference is 5391 for queue0.tx_packets but for > mac_stats.total_pkts_txd is 376 > Everything else is matching up. > > Before (working) > dev.igb.1.queue0.tx_packets: 25359165 > dev.igb.1.queue0.rx_packets: 18526094 > dev.igb.1.mac_stats.total_pkts_recvd: 25508763 > dev.igb.1.mac_stats.total_pkts_txd: 16831587 > > > After(working) > dev.igb.1.queue0.tx_packets: 25364597 > dev.igb.1.queue0.rx_packets: 18531398 > dev.igb.1.mac_stats.total_pkts_recvd: 25514009 > dev.igb.1.mac_stats.total_pkts_txd: 16836833 > > > Another interesting stat is > before_notworking:dev.igb.1.interrupts.tx_queue_empty: 16646890 > after_notworking:dev.igb.1.interrupts.tx_queue_empty: 16647266 > > The difference here is exactly 376 which is the number of packets that th= e > device actually claims to have transmitted. It=E2=80=99s as though it did= n=E2=80=99t see > the other packets en-queued in the ring descriptor. > > > I can=E2=80=99t do netstat just for arp as these are coming in a tunnel(P= ackets > don=E2=80=99t=E2=80=99 show up as arp on the interface). However, I did s= ee the packet rate > was about 500 packets/sec > > > >(You can netstat -z to clear the counters between runs.) > > > >Cheers, > >Hiren > >
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